Semiotic analysis is the study of signs. It involves deconstructing elements of a Media text, describing them and identifying the subconscious impact this has on an audience. Every human on the planet processes semiotics, however their meaning can change from person to person and even between different cultures.
Vladimir Propp's character theory categorizes typical character archetypes. This theory can be used to help identify key characters within a narrative and how they follow or subvert typical expectations of the audience in relation to their actions. Apply this theory through identifying key characters, associating them with a role and then backing this association up with evidence from your chosen media text.
Todorov theorized that all narratives contain five 'stages', through which the main characters will travel. These stages can be very traditionally followed to create a simplistic and satisfying narrative, or the sequence is sometimes displayed out of sequence to create enigmas for the audience.
Binary Opposites theorizes that all narratives are driven through two oppositional forces. The struggle between these forces and the eventual outcome are considered the core of the narrative. Examples of these would be Good vs Evil (Star Wars), Man vs Nature (Avatar) or Natural vs Supernatural (IT). When analyzing a Media text you should look for signs of these opposites and relate them to this theory if they are present.
Enigma Codes are one component of Roland Barthe's Codes theory, in which he theorized that narratives will contain certain 'codes' or recognizable techniques to draw audience attention. Enigma Codes are one of the most common so it is important to understand them; they are mysteries created within a narrative that drive the interest of the audience to continue watching. These can range from being the backbone of the narrative (Sherlock; solving the enigma of a crime) or can be used to create suspense in a series through an enigma that will not be resolved until later episodes (Avengers: Infinity War).
All screencasts below cover theory that is required for the A-level syllabus. If you are a GCSE student, feel free to have a go at learning about some. If you are able to understand and apply some of these, it will help you attain a Level 9. These are by no means essential learning though.
This is the most advanced narrative theory and should be employed by those looking to attain a Level 9/A* grade.